GUI Scaling and new blocks

Two inventory convenience updates: A /clear command now clears the inventory and the keyboard keys 1-9 let's you flip itemstacks between your hotbar and the currently hovered item.

Update on the Physics system to allow stepping on half blocks without jumping

Added GUI Scaling - which is necessary so the GUI can resized to fit your screen size. This is where the GUI System shines - since everypart of the GUI (buttons, text, shadows, borders, lines, sliders, ...) is drawn in code, it can be freely resized without blur.

New blocks! Vintagestory now has fences, doors, stairs, slabs, glass and polished stone. Some of them still have a very rough implementation, but the placement of stairs and fence works and doors can be interacted with already.

Saraty remade the rock textures and made polished stone, which looks like awesome material for some epic builds.